Silicon doping effect on the crystallization behavior of Ge 2 S b 2 T e 5 film

Pure Ge 2 Sb 2 Te 5 thin films and Si‐doped Ge 2 Sb 2 Te 5 thin films were deposited by electron beam evaporation method. The property of Si‐doped Ge 2 Sb 2 Te 5 films are compared with that of pure Ge 2 Sb 2 Te 5 films. Through in situ resistance measurement and I – V characteristic tests, an improvement of amorphous stability and an increase of crystalline resistivity are observed. The phase‐separation phenomenon is observed in TEM pictures and a distinct decrease of crystal grain size in Si‐doped Ge 2 Sb 2 Te 5 thin film can be seen in HRTEM pictures. A blueshift and broadening of peaks after Si doping in Raman spectra are found and from absorption spectra, the broadening of crystalline optical bandgap in Si‐doped Ge 2 Sb 2 Te 5 thin film is proved. Finally, the behavior of doped Si atoms is proposed to explain the effect of Si doping in Ge 2 Sb 2 Te 5 thin film.